A parking sensor that sings at a dry leaf

A parking sensor is worth the noise if the noise means the bumper is about to meet something. This month the desk heard a lot of noise that meant a dry leaf, a change in the slope, or a kerb we were not close to. The beep had become weather.

Useful, or only loud

We took the same slow approach to a plain wall, then to an empty marked bay, then along a kerb that rose slightly. The wall was honest: the tone climbed, and it matched the picture. The empty bay was not. One car sang at the painted line as if it were a post. Another stayed quiet until the bumper was actually near the kerb, which is the behaviour we want, and then sang again on the way out at nothing we could see on the ground.

There is no score and no table. The check is whether a driver can believe the next beep. A sensor that cries at a slope teaches the driver to ignore it, and an ignored sensor is the one that was there for the post.

What we will keep

If the warning matches the obstacle, we say it is doing the job. If it sings at an empty kerb, we say that, and we say it beside the camera and the mirrors, because those are the tools a driver still has when the beep has spent its credibility. The leaf is not the story. The lost credibility is.